What is the mass of an object if its height is 10 meters above ground and its gravitational potential energy (GPE) is 3920 Joules? Remember Gravity = 9.8 meters per seconds squared

The bond energy for the van der waals bond between two helium atoms is 7.9×10−4ev. assuming that the average kinetic energy of a helium atom is (3/2)kbt, at what temperature is the average kinetic energy equal to the bond energy between two helium atoms